Triggering of restraining means, such as airbags of different design or triggerable seat belt tensioners, is nowadays effectuated on the basis of sensors for detecting acceleration in the longitudinal direction and the transverse direction of the vehicle, i.e., the x and y directions. In addition, analysis of upfront or pre-crash radar sensors is known which may trigger occupant protection means in particular, such as adjustment of a seat backrest or closing of the vehicle windows or the sun roof. When driving over or through road bumps, such as a pothole, a curb, a wooden tie, a railroad track or even a ditch, relatively high acceleration values are detected for a short time in the x/y plane; however, deployment of the restraining means is not necessary in such “misuse” driving situations, as they are known. Today's systems for triggering restraining devices in vehicles may not unambiguously differentiate such operating states, such as off-roading, from an actually dangerous driving situation, such as an imminent crash.